title: Spatiotemporal analysis of cell response to a rigidity gradient: a quantitative study using multiple optical tweezers.
abstract: We investigate the dynamic response of single cells to weak and local rigidities, applied at controlled adhesion sites. Using multiple latex beads functionalized with fibronectin, and each trapped in its own optical trap, we study the reaction in real time of single 3T3 fibroblast cells to asymmetrical tensions in the tens of pN x microm(-1) range. We show that the cell feels a rigidity gradient even at this low range of tension, and over time develops an adapted change in the force exerted on each adhesion site. The rate at which force increases is proportional to trap stiffness. Actomyosin recruitment is regulated in space and time along the rigidity gradient, resulting in a linear relationship between the amount of recruited actin and the force developed independently in trap stiffness. This time-regulated actomyosin behavior sustains a constant and rigidity-independent velocity of beads inside the traps. Our results show that the strengthening of extracellular matrix-cytoskeleton linkages along a rigidity gradient is regulated by controlling adhesion area and actomyosin recruitment, to maintain a constant deformation of the extracellular matrix.
authors.affiliation: Complexes Macromoléculaires en Cellules Vivantes, Institut Jacques Monod, Unité Mixte de Recherche 7592, Centre National de Recherche Scientifique, Université Paris Diderot-Paris 7, Université Pierre et Marie Curie-Paris 6, 75251 Paris, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Allioux-Guérin
authors.forename: Delphine
authors.initials: D
authors.lastname: Icard-Arcizet
authors.forename: Christiane
authors.initials: C
authors.lastname: Durieux
authors.forename: Sylvie
authors.initials: S
authors.lastname: Hénon
authors.forename: François
authors.initials: F
authors.lastname: Gallet
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Mevel
authors.forename: Marie-Jo
authors.initials: MJ
authors.lastname: Masse
authors.forename: Marc
authors.initials: M
authors.lastname: Tramier
authors.forename: Maïté
authors.initials: M
authors.lastname: Coppey-Moisan
mesh_terms: D016475:3T3 Cells; D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology*; D002468:Cell Physiological Phenomena / Q000502:physiology*; D003599:Cytoskeleton / Q000502:physiology; D004548:Elasticity; D005109:Extracellular Matrix / Q000502:physiology; D005347:Fibroblasts / Q000502:physiology*; D005353:Fibronectins / Q000378:metabolism; D016014:Linear Models; D051379:Mice; D009038:Motion; D024462:Myosin Type II / Q000378:metabolism; D052898:Optical Tweezers; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D000199:Actins; D005353:Fibronectins; D000205:Actomyosin; D024462:Myosin Type II